ORIGINAL ARTICLE

Reliability and Validity of the Adapted Turkish Version of the Early-onset Scoliosis-24-Item Questionnaire (EOSQ-24) Halil G. Demirkıran, MD,* Gizem I˙. Kınıklı, PT, PhD,w Zeynep D. Olgun, MD,* Saygın Kamacı, MD,* Yasemin Yavuz, MD,z Michael G. Vitale, MD, MPH,y and Muharrem Yazici, MD*

Introduction: Early-onset scoliosis (EOS) can have negative effects on the developing thorax, lungs, and quality of life in general. Children with EOS can face various health problems and require recurring hospitalization and surgeries. Radiographic parameters are insufficient to evaluate the severity and efficacy of treatment in EOS. Early-onset Scoliosis Questionnaire (EOSQ)-24 questionnaire is a new instrument developed for this specific age group. To date, reliability of this questionnaire has not yet been interrogated in wide patient groups from different cultures. The aim of this study was to evaluate the validity and reliability of culturally adapted Turkish version of the EOSQ-24. Methods: Forward translation and back translation of the English version of the EOSQ-24 was done, and all steps for crosscultural adaptation process were performed properly by an expert committee. Turkish version of the EOSQ-24 and Child Health Questionnaire-Parent Form-50 (CHQ-PF-50) were applied to 61 (24 male, 37 female) EOS patients. The average age of these patients was 9.1 ± 3.1 years (0.4 to 14.3 y), and 50 of them had undergone surgical treatment. Data quality was assessed by mean, median, percentage of missing data, and extent of ceiling and floor effects. Reliability was assessed by internal consistency using Cronbach’s a and item-total correlations. The construct validity was evaluated by comparing the results of the EOSQ-24 with the Turkish version of the CHQ-PF-50. Subgroup analyses were applied for sex, diagnosis, treated/untreated, mobilization ability, and complications. Results: The item response to the EOSQ-24 was high with a small number of missing answers (1.6% to 3.3%). Of the 24 items, 22 were evenly distributed. This resulted in a floor effect in 0% to 21.7% of patients, and a ceiling effect in 1.6% to 68.3%. From the *Department of Orthopaedics and Traumatology, Faculty of Medicine; wDepartment of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Hacettepe University; zDepartment of Biostatistics, Faculty of Medicine, Ankara University, Ankara, Turkey; and yDepartment of Orthopaedic Surgery, Columbia University, New York, NY. The authors declare no conflicts of interest. Reprints: Muharrem Yazici, MD, Department of Orthopaedics and Traumatology, Faculty of Medicine, Hacettepe University, Ankara, 06230, Turkey. E-mail: [email protected]. Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Website, www. pedorthopaedics.com. Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.

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The calculated Cronbach’s a for the 24-item scale was 0.909, indicating excellent reliability. Construct validity showed that high correlations between the EOSQ and the CHQ by means of similar domains. Correlation coefficient was between 0.348 and 0.688 (P = 0.0001). Subgroup analyses also showed significant difference in treated/untreated patients (P = 0.032) and mobilization ability (P = 0.001). Discussion: The Turkish adaptation of the EOSQ-24 exhibits favorable psychometric properties and excellent reliability, validating its use in this population. Level of Evidence: Level III—diagnostic study. Key Words: early-onset scoliosis, EOSQ-24, validity, reliability, health-related quality of life (J Pediatr Orthop 2015;35:804–809)

E

arly-onset scoliosis (EOS) is a lateral curvature of the spine observed in children below 10 years of age. It has the potential to cause significant morbidity and serious harm to patients and their quality of life through rapid progression, resulting in severe and complex deformities. The young age and large growth potential in these patients has led physicians to consider fusionless methods of surgical treatment; however, these methods require periodic lengthenings and repeated hospitalizations, potentially adding to the physical and psychological burden experienced by the growing child and their family. Technological advances in implant technology and intensive care systems have led to the surgical treatment of early-onset spinal deformities becoming almost routine. As with most spinal disorders, the outcomes of treatment used to be evaluated using objective measures such as radiographic parameters. However, with a growing interest on the impact of treatment on health-related quality of life, outcome measures that assess the subjective response of patients to their disease, and treatment approaches have been developed for many conditions. Such a measure for EOS has been recently developed by Corona et al1 using a review of the literature and interviews of caregivers of EOS patients. This questionnaire, the Early-onset Scoliosis Questionnaire (EOSQ), includes 33 items in 13 domains and was designed to measure the quality of life and caregiver burden in EOS patients. It was constructed initially in English, in the United States, and has been shown J Pediatr Orthop



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to have high internal consistency and reliability. After its initial publication, it has been modified into the current form, the EOSQ-24.2 Previous research has shown that health-related quality of life measures need to be not only translated but also culturally adapted in order for them to retain consistency and validity for the evaluation of a new population. This is important, especially in rare disorders, such as EOS, where multicenter multinational cooperation is essential to amass larger patient series and compare outcomes on a multinational level. The Turkish version of the Child Health Questionnaire-Parent Form (CHQ-PF-50) was used to evaluate the health-related quality of life of children from the point of view of their parents’ to compare with the EOSQ-24 results. The aim of this study was to translate and provide evidence for the reliability and validity of the Turkish version of the EOSQ-24.

METHODS The study was approved by the Hacettepe University Ethics Committee (HEK08/93-10) and took place from January 2013 to August 2013. All participants were provided with written informed consent forms before their participation.

Translation and Cultural Adaptation The internationally accepted forward-back translation technique was used.3 First, the original questionnaire was translated from English into Turkish independently by 2 Turkish individuals, 1 of whom had no medical background. The native language of both translators was Turkish and they were both fluent in English. These 2 translations were later put together and cultural adaptation was considered by an expert committee consisting of 2 spine surgeons, 1 physiotherapist, 1 epidemiologist, and the 2 translators. After this, 2 native English speakers with a good command of the Turkish language separately translated the final Turkish translation back into English. Both translators were unaware of the purpose of the study and had no access to the original questionnaire. After discussing the discrepancies, the committee approved the final Turkish version of the EOSQ-24. The translated and culturally adapted version of the EOSQ-24, and the previously validated outcome measure, the CHQ-PF-50, were then administered to the parents of EOS patients during routine follow-up visits. Parents filled out the new questionnaire themselves and were asked to remark on the relevance and understandability of the questions. CHQ-PF-50 was chosen because it is currently the only cross-culturally adapted outcome measure directed toward children.

Outcome Measures The EOSQ-24 The EOSQ-24 represents a subjective, parent-based, and self-report questionnaire. It includes 11 separate items in 24 questions. The domains are general health, Copyright

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Early-onset Scoliosis-24-Item Questionnaire

pain, pulmonary function, mobility, physical function, daily living, fatigue, emotion, parental burden, financial burden, and satisfaction.1 Parents rated whether they considered each item relevant to their child’s health condition (relevance), and whether the items were clear enough for them to understand (clarity). Relevance and clarity were rated using a 5-point Likert scale (eg, 1: “not relevant at all” to 5: “extremely relevant”).

The CHQ-PF-50 The Child Health Questionnaire (CHQ) is a selfadministered or parent proxy assessment of physical, psychological, and social health status of children 5 to 18 years of age.4,5 This questionnaire contains 15 specific categories related to physical and emotional well-being. Global general health, physical functioning, role of emotional behavior, role of the physical, bodily pain, emotional behavior, global emotional behavior, mental health, change health, self-esteem, general health, the emotional impact on the parent, the impact on the time of the parent, family activity, and family cohesion are evaluated. The maximum score possible from all sections is “100,” and the worst possible score is “0.” This questionnaire measures the child’s general health condition, and was developed for researchers and clinicians who study children’s functional activities. The mothers were informed in detail about the protocol before filling it out and then informed of the final score. The cross-cultural adaptation and validation of the Turkish version of the parent’s version of the CHQ is available.6

Data Analysis All statistical analyses were performed using PASW Version 18.0 (SPSS Inc., Chicago, IL), with a level of TABLE 1. Demographic Characteristics n Sex (%) Male Female Median age of child (y) Median age of primary caregiver (y) Median age at surgery (y) Median age at diagnose (y) Diagnose (%) Congenital Neuromuscular Split cord Idiopathic Syndromic Other Status (%) Preoperative Postoperative Complication (%) No Yes Ambulation (%) Paraplegic Full-weight bearing mobilization Limping

24 37 61 45 61 61

Statistics

9.6 35 5.3 1.8

39.3 60.7 (0.4-14.3) (27-58) (0.4-12.8) (0-10)

18 12 17 6 6 2

29.5 19.7 27.9 9.8 9.8 3.3

11 50

18.0 82.0

43 18

70.5 29.5

14 39 8

23.0 63.9 13.1

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significance of 5%. The measurement properties analyzed in this study for the instruments included internal consistency, validity, and ceiling and floor effects. Total scores were compared using the analysis of variance and the Student t test according to variables of sex, duration of follow-up, age at diagnosis/surgery, age of parents, ambulatory status, and surgical status.

Internal Consistency Internal consistency was assessed using the Cronbach coefficient alpha. This test indicates the homogeneity of the distinguishing factors between the items within a questionnaire or subdomains of the questionnaire. “Cronbach’s alpha” is also used to determine the interrelatedness among the items of a questionnaire. We used the test “Cronbach alpha if item deleted” to verify Cronbach alpha with the exclusion of each of the questions, one at a time. A low Cronbach alpha indicates low correlation between items designed to measure the same construct, whereas a very high Cronbach alpha indicates



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redundancy between 1 or more items. The recommended value for the Cronbach a is between 0.70 and 0.95.7

Validity Construct validity refers to “the extent to which scores on a particular instrument relate to other measures in a manner that is consistent with theoretically derived hypotheses concerning the concepts that are being measured.”7 The construct validity was evaluated by comparing the results of the EOSQ-24 with the Turkish version of the CHQ-PF-50. The Spearman rank correlation was used to assess the association between domains. Because these questionnaires assess similar (but not identical) constructs, a positive correlation of at least moderate strength was expected (rZ0.5).7,8 A correlation coefficient 0.6 were considered low, moderate, and strong, respectively.9

The Ceiling and Floor Effects The ceiling and floor effects represent limitations of an instrument’s ability to assess the entire spectrum of a condition’s severity with the items it contains. The ceiling

TABLE 2. Internal Consistency Analysis of the EOSQ-24 Domains General health Q1 Q2 Pain Q3 Q4 Pulmonary function Q5 Q6 Mobility Q7 Physical function Q8 Q9 Q10 Daily living Q11 Q12 Fatigue Q13 Q14 Emotion Q15 Q16 Parental burden Q17 Q18 Q19 Q20 Q21 Financial burden Q22 Satisfaction S23 S24

Scale Mean if Item Deleted

Scale Variance if Item Deleted

Corrected Item-total Correlation

79.6 78.8

265.1 264.1

0.371 0.341

78.7 78.4

255.8 258.1

0.503 0.531

78.2 78.0

256.7 257.9

0.432 0.476

79.3

245.5

0.593

78.9 78.5 79.4

243.0 244.7 245.9

0.674 0.608 0.570

78.9 79.1

240.9 243.9

0.698 0.630

78.5 78.6

254.9 250.1

0.528 0.622

79.3 79.3

258.2 249.2

0.453 0.641

79.9 79.3 79.7 79.3 79.0

260.2 252.6 258.3 255.9 258.5

0.418 0.582 0.474 0.467 0.478

79.9

264.9

0.272

78.9 78.6

255.1 258.3

0.508 0.458 a

Cronbach’s Alpha if Item Deleted 0.421 0.908 0.909 0.908 0.906 0.906 0.614 0.908 0.907 0.904 0.817 0.902 0.904 0.905 0.684 0.902 0.903 0.805 0.906 0.904 0.672 0.907 0.903 0.777 0.908 0.905 0.907 0.907 0.907 0.910 0.809 0.906 0.907 0.909*

*Alpha coefficients for the total EOSQ scales. Q indicates Question.

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Early-onset Scoliosis-24-Item Questionnaire

and floor effects refer to content validity, and their presence indicates that extreme items are missing in the scale. Descriptive statistics (mean values, SDs, and quartiles) were calculated to determine distribution and ceiling/floor effects.10,11

been changed. For a better understanding please refer to the Appendix, Supplemental Digital Content 1, http://links. lww.com/BPO/A31 and Supplemental Digital Content 2, http://links.lww.com/BPO/A32.

RESULTS

The calculated Cronbach’s a for the 24-item scale was 0.909, indicating excellent reliability. The range for the 9 subscales was also calculated and found to be 0.421 to 0.908. Cronbach’s a if item deleted (for each question) varied from 0.902 to 0.908. Item-to-total correlation coefficients were calculated for the items of each section of the EOSQ-24. The corrected item-to-total correlations were acceptable for every EOSQ-24 subscale ranging between 0.272 and 0.698 (Table 2).

Internal Consistency

The parents of 61 (male, 24; female, 37) patients with EOS filled out the questionnaire. The patient population consisted of a heterogenous group of children with EOS of diverse etiologies and stages of treatment (Table 1).

Translation and Cultural Adaptation The translators had difficulty translating the phrase “shortness of breath,” and the words “burden” and “fatigue.” The committee decided to translate “pain” as “discomfort” in the second domain, as a lack of understanding of the term could affect scores on the questionnaire. In addition, the committee decided to translate “fatigue” as “energy level” in the seventh domain. As its perception in its original form may be influenced by cultural differences, these 2 domains have

Validity Correlations between the EOSQ-24 and CHQ-PF-50 domains were tested for construct validity. All correlation coefficients for the comparisons described, including the comparison between the EOSQ-24 subscale scores and

TABLE 3. Validity of the EOSQ-24 in Comparison With the CHQ-PF-50 Global Health

Items General health r P Pain r P Pulmonary function r P Mobility r P Physical function r P Daily living r P Fatigue r P Emotion r P Parental burden r P Financial burden r P Satisfaction r P

Physical Functioning

Role/ Emotional Behavior

Bodily Pain

Behavior

Mental Health

SelfEsteem

General Health Perceptions

Emotional Impact on Parent

0.424** 0.001

0.245 0.061

0.078 0.557

0.364** 0.005

 0.089 0.503

0.019 0.884

 0.142 0.283

 0.051 0.701

 0.003 0.979

0.295* 0.023

0.281* 0.031

0.118 0.373

0.595*** 0.000

 0.128 0.336

0.094 0.481

 0.074 0.575

 0.111 0.403

0.002 0.990

0.399** 0.002

0.264* 0.042

0.154 0.241

0.396** 0.002

0.027 0.835

0.042 0.749

 0.061 0.641

0.073 0.578

0.078 0.553

0.463*** 0.000

0.462*** 0.000

0.221 0.087

0.244 0.058

0.026 0.845

0.111 0.396

0.360** 0.004

0.289* 0.024

0.477*** 0.000

0.474*** 0.000

0.668*** 0.000

0.432** 0.001

0.197 0.132

0.141 0.282

0.278* 0.031

0.168 0.199

0.182 0.165

0.288* 0.026

0.569*** 0.000

0.549*** 0.000

0.372** 0.003

0.368** 0.004

0.214 0.100

0.246 0.058

0.384** 0.002

0.246 0.058

0.246 0.058

0.360** 0.005

0.246 0.060

0.197 0.134

0.391** 0.002

0.149 0.259

0.290* 0.026

0.098 0.462

0.132 0.318

0.228 0.082

0.258* 0.047

0.539*** 0.000

0.439*** 0.000

0.308* 0.017

0.228 0.080

0.514*** 0.000

0.249 0.055

0.208 0.111

0.422** 0.001

0.383** 0.003

0.485*** 0.000

0.447*** 0.000

0.274* 0.035

0.187 0.156

0.347** 0.007

0.426** 0.001

0.329* 0.011

0.523*** 0.000

0.094 0.472

0.299* 0.019

0.334** 0.009

0.023 0.862

0.120 0.356

0.183 0.159

0.268* 0.036

0.202 0.119

0.348** 0.006

0.267* 0.038

0.317* 0.013

0.179 0.167

0.164 0.207

0.082 0.529

0.380** 0.002

0.384** 0.002

0.149 0.251

0.164 0.207

r indicates correlation coefficient. *P < 0.05. **P < 0.01. ***P < 0.001.

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CHQ-PF-50 subscale scores are displayed in Table 3 (see Appendix, Supplemental Digital Content 1, http://links.lww.com/BPO/A31 and Supplemental Digital Content 2, http://links.lww.com/BPO/A32). Good correlations were found between the Child’s Global Health subscale of the CHQ-PF-50 and General Health subscale of the EOSQ-24 (r = 0.424; P = 0.001). Pain subscales of both questionnaires were considered highly moderate (r = 0.595; P = 0.000). The mobility subscale of the EOSQ-24 was moderately correlated with the child’s physical activity subscale of the CHQ-PF-50 (r = 0.462; P = 0.000). In addition, the physical function subscale of the EOSQ-24 was strongly correlated with the child’s physical activity subscale of the CHQ-PF-50 (r = 0.668; P = 0.000). The daily living subscale of the EOSQ-24 was moderately correlated with the child’s global health and child’s physical activities subscales of the CHQ-PF-50, respectively (r = 0.569, P = 0.000; r = 0.549, P = 0.000). The emotion subscale of the EOSQ-24 was also moderately correlated with the behavior subscale of the CHQ-PF-50 (r = 0.514; P = 0.000). The parental burden subscale of the EOSQ-24 was moderately correlated with the you and your family subscale of the CHQ-PF-50 (r = 0.523; P = 0.000).



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EOSQ-24 to be within the recommended range of values (0.70 to 0.95).7 The original version of the EOSQ-24 was not assessed in terms of internal consistency. Unfortunately, there is no validation study in the literature of the EOS questionnaire in other languages to which to compare Cronbach’s alpha. The mean value we obtained from the study was 0.911. This may be owing to the fact that the published data are the result of the preliminary version of the questionnaire, which consisted of 33 items.1 After analysis, 6 items were found not to contribute sufficiently to the scale and were omitted.1 The results of the item analysis showed that the item-total correlation values were above 0.20 for all items, and none of the items increased the overall Cronbach’s a value if omitted. This indicates that all items contribute to the scale. The lowest Cronbach’s a value (0.289) was found in item 22, which is a question that regards financial status. This may be owing to the fact that most of the patients who participated in the study are covered by government-issued insurance. This effect has been observed in other outcome measures adapted into the

The Ceiling and Floor Effect The item response to the EOSQ-24 was high with a small number of missing answers (1.6% to 3.3%). Twentytwo of the items had evenly distributed responses over the 5 possible answers. No participant chose answer 1 in item 4 and answer 2 in item 6. The median of items 1, 7, 15, 16, 17, 18, 19, 20, 21 was found to be 3. Items 2, 3, 4,5, 6, 8, 9, 11, 12, 13, 14, 23, 24 were left-skewed, with items 5 and 6 highly left-skewed. Items 10 and 22 were right-skewed. This resulted in a floor effect in 0% to 21.7% of patients and a ceiling effect in 1.6% to 68.3% (Table 4) (see Appendix, Supplemental Digital Content 1, http://links.lww.com/ BPO/A31 and Supplemental Digital Content 2, http:// links.lww.com/BPO/A32). The results were analyzed according to the variables of sex, duration of follow-up, and age at diagnosis or surgery. None of these variables were found to significantly affect the scores; however, ambulatory patients (P = 0.001) and those who had undergone surgical treatment scored significantly higher (P = 0.032).

DISCUSSION Patients with EOS are, by definition, young children who must undergo a protracted treatment process and often repeated surgeries. Untreated EOS generally results in severe disfiguration of the trunk, causing pulmonary and cardiovascular compromise and can negatively impact a patients quality of life as much as their life expectancy if not treated appropriately. Until now, an objective health-related quality of life measure specific to the unique aspects of EOS treatment was not available. With the development of the EOSQ-24, this gap has now been addressed. A cultural and linguistic adaptation of the EOSQ-24 questionnaire was done, and its reliability and validity for Turkish patients were evaluated. In the first part of the study, the internal consistency analysis using Cronbach’s alpha showed the Turkish

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TABLE 4. Data Quality With the Floor and Ceiling Effect of the EOSQ-24 (n = 61) n General health Q1 61 Q2 59 Pain Q3 59 Q4 61 Pulmonary function Q5 61 Q6 60 Mobility Q7 61 Physical function Q8 61 Q9 61 Q10 60 Daily living Q11 60 Q12 61 Fatigue Q13 60 Q14 60 Q15 60 Q16 60 Parental burden Q17 61 Q18 60 Q19 61 Q20 60 Q21 61 Financial burden Q22 61 Satisfaction Q23 61 Q24 61

Mean (SD)

Median

Missing Floor Ceiling (%) (%) (%)

2.84 (0.78) 3.63 (0.95)

3 4

0.0 3.3

3.3 1.7

1.6 18.6

3.71 (1.12) 3.95 (0.99)

4 4

3.3 0.0

1.7 0.0

32.2 37.7

4.16 (1.27) 4.43 (1.03)

5 5

0.0 1.6

6.6 5.0

60.7 68.3

3.07 (1.49)

3

0.0

21.3

26.2

3.34 (1.49) 3.72 (1.58) 2.88 (1.53)

4 4 2

0.0 0.0 1.6

14.8 14.8 21.7

32.8 52.5 23.3

3.40 (1.55) 3.39 (1.48)

4 4

1.6 0.0

15.0 9.8

38.3 34.4

3.83 3.68 3.08 3.02

(1.18) (1.33) (1.12) (1.24)

4 4 3 3

1.6 1.6 1.6 1.6

3.3 6.7 5.0 13.3

38.3 38.3 15.0 15.0

2.46 3.17 2.74 3.08 3.39

(1.06) (1.12) (1.06) (1.23) (1.13)

3 3 3 3 3

0.0 1.6 0.0 1.6 0.0

19.7 8.3 16.4 13.3 4.9

3.3 15.0 3.3 13.3 19.7

2.52 (1.07)

2

0.0

16.4

6.6

3.52 (1.18) 3.90 (1.06)

4 4

0.0 0.0

6.6 4.9

21.3 31.1

Q indicates Question.

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Turkish language.12 The second lowest values were observed in the pain domain, which may be a result of EOS being a painless condition. This effect has also been previously observed in conditions that are similar in nature.12 Considering validity, comparison of correlations among the related domains of the Turkish version of the EOSQ-24 and the CHQ-PF-50 questionnaires showed that the correlations were moderately high. Our results demonstrated significant correlations between the EOSQ24 and the CHQ-PF-50. Overall, the difference in focus of these questionnaires may explain the difference in the strength of the associations. The wide range of score distribution among parents’ answers may be explained by the heterogeneity of our EOS population consisting of patients of various ages, EOS etiologies, and stages of treatment. The score distribution of the Turkish version of this questionnaire indicated that it responded to patient-perceived outcomes well. However, the presence of right skewedness in 2 of the pulmonary and 1 of the satisfaction items is likely because of the generally good pulmonary function and independent mobility status of our patients, and therefore these items exhibited a high ceiling effect. In conclusion, the EOSQ-24 provides a reliable and valid assessment tool for patients with EOS. The internal consistency of the Turkish version of the EOSQ-24 was found to be acceptable, and its validity was confirmed. However, it is difficult to evaluate variables such as age, neurological status, associated pulmonary problems, and number of surgeries using a standard outcome questionnaire. Future studies should be conducted with fewer variables and more homogenous diagnoses.

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Early-onset Scoliosis-24-Item Questionnaire

REFERENCES 1. Corona J, Matsumoto H, Roye DP, et al. Measuring quality of life in children with early onset scoliosis: development and initial validation of the Early Onset Scoliosis Questionnaire. J Pediatr Orthop. 2011;31:180–185. 2. Matsumoto H, McCalla DJ, Park HY, et al. The Early-Onset Scoliosis 24 Item Questionnaire (EOSQ-24) Reflects Changes in Quality of Life and Parental Burden after Growing Rod Surgery. 6th International Congress on Early Onset Scoliosis and Growing Spine (ICEOS), November 15–16, 2012, Dublin, Ireland. J Children Orthop. 2012;6:439–459. 3. Beaton DE, Bombardier C, Guillemin F, et al. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine. 2000;25:3186–3191. 4. Schoenmakers MA, Uiterwaal CS, Gulmans VA, et al. Determinants of functional independence and quality of life in children with spina bifida. Clin Rehabil. 2005;19:677–685. 5. Landgraf JM. Measuring health-related quality of life in pediatric oncology patients: a brief commentary on the state of the art of measurement and application (discussion). Int J Cancer. 1999; 83(S12):147–150. 6. Ozdogan H, Ruperto N, Kasapc¸opur O, et al. The Turkish version of the childhood health assessment questionnaire (CHAQ) and the child health questionnaire (CHQ). Clin Exp Rheumatol. 2001;19(suppl 23):S158–S162. 7. Terwee CB, Bot SD, de Boer MR, et al. Quality criteria were proposed for measurement properties of health status questionnaires. J Clin Epidemiol. 2007;60:34–42. 8. Kirshner B, Guyatt G. A methodological framework for assessing health indices. J Chronic Dis. 1985;38:27–36. 9. Chapter 5: Correlation: A measure of Relationship. In: Hinkle DE, Wiersma W, Jurs SG, eds. Applied Statistics for the Behavioral Siences. Boston, Mass: Houstoun Mifflin; 1998:105–131. 10. Ware JE. Conceptualizing and measuring generic health outcomes. Cancer. 1991;67(S3):774–779. 11. Stratford PW. Confidence limits for your ICC. Phys Ther. 1989; 69:237–238. 12. Alanay A, Cil A, Berk H, et al. Reliability and validity of adapted Turkish Version of Scoliosis Research Society-22 (SRS-22) questionnaire. Spine. 2005;30:2464–2468.

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809

Reliability and Validity of the Adapted Turkish Version of the Early-onset Scoliosis-24-Item Questionnaire (EOSQ-24).

Early-onset scoliosis (EOS) can have negative effects on the developing thorax, lungs, and quality of life in general. Children with EOS can face vari...
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